CVE-2026-33797 Junos OS and Junos OS Evolved: An attacker sending a specific genuine BGP packet causes a BGP reset

High 7.1 Published 9 Apr 2026 Updated 23 Apr 2026

An unauthenticated adjacent attacker can cause a persistent Denial of Service by sending specific BGP packets to reset established sessions.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-33797?

CVE-2026-33797 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker, sending a specific genuine BGP packet in an already established BGP session to reset only that session causing a Denial of Service (DoS).

An attacker repeatedly sending the packet will sustain the Denial of Service (DoS).This issue affects Junos OS:

* 25.2 versions before 25.2R2

This issue does not affect Junos OS versions before 25.2R1.

This issue affects Junos OS Evolved: * 25.2-EVO versions before 25.2R2-EVO

This issue does not affect Junos OS Evolved versions before 25.2R1-EVO.

eBGP and iBGP are affected. IPv4 and IPv6 are affected.

Weakness: CWE-20

Which versions are affected by CVE-2026-33797?

It affects 2 products.

Products include Juniper Junos, Juniper Junos Os Evolved.

How do I fix CVE-2026-33797?

No fix has been published for CVE-2026-33797 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-33797 being exploited?

There is no known exploitation of CVE-2026-33797 in the wild and no public exploit code.

All Juniper Junos vulnerabilities

Sources

Also known as GHSA-3rpc-j6fw-646r.